Combination lock construction



April 14, 1959 c. N. SMITH ETAL 1 COMBINATION LOCK CONSTRUCTION FiledSept 19. 1955 5 Sheets-Sheet 1 4 INE/ENTOR S ChwrlesNonws Swill g;Frederic]; elBremer d 3| ATTORNEYS April 14,1959 c. N. SMITH ETAL j 2,881,61 2;

COMBINATION LOCK CONSTRUCTION Filed Sept. 19. 1955 5 Sheets-Sheet 2INVENTORS Chwrbes Norris Smilz m Frederalz J. Bremer '2 ATTORNEYS P 1959C.'N. YSMITH E TALQ I 7 2,881,612

COMBINATION LOCK CONSTRUCTION Filed Sept." 19. 1955 5 Sheets-Sheet 3INVEN TORS Charles Norris Smifilz g Frederick dBremer d ATTORNEYS April14, 1959 c. N. SMITH ETAL COMBINATION LOCK CONSTRUCTION 5 Sheets-Sheet 4Filed Sept. 19. 1955 INVENTORS Charles Norris J Bremer '52 M} Frederia'k ATTORNEY;

April 14, 1959 c. N; SMITH ET AL 2,881,612

COMBINATION LOCK CONSTRUCTION I 5 Sheets-Sheet 5 Filed Sept. 19. 1955 mw Q a I I m H v L H H MM w l a w d 6 I a m H I I Frederick J BrennerATTORJVEKQ United States Patent() COMBINATION LOCK CONSTRUCTION CharlesNorris Smith, North Canton, and Frederick J. Bremer, Hamilton, OhioApplication September 19, 1955, Serial No. 535,026

13 Claims. (Cl. 70-302) Our invention relates to improvements incombination lock construction and more specifically to a combinationlock construction having improved manipulation-proof features. Certainprior constructions of combination locks have included the usual slottedtumblers rotatably mounted on a dial shaft and working in conjunctionwith a fence for withdrawing certain bolt work when properly set.Further in some cases the dial shaft has been provided with a cam memberupon which the fence normally rides, spaced radially from the outerextremity of the tumblers, with the dial shaft and consequently the cammember being axially movable to permit the fence to engage in thetumbler slots when these slots are aligned.

Some of these prior constructions of combination locks have beenrelatively manipulation-proof in theoretical design, that is, if it werepossible to construct these locks exactly according to specification. Itis almost impossible, however, to construct these locks exactlyaccording to specification even though each lock were handmade, and thetolerances required for modern mass production of such locks hascompletely eliminated any consideration of having the locks perfectlyuniform and to exact size, that is, to the point of making themmanipulation-proof.

Taking, for instance, a combination lock having the usual axiallymovable dial shaft and a tapered cam member upon which the fence mayride during the setting of the tumblers, because of the usual massproduction discrepancies, it is possible for an unauthorized person tomeasure, the exact point at which the fence strikes the tapered surfaceof the cam member when the dial shaft is moved between its axialpositions. Further, by taking a series of measurements during a setpattern of manipulation of the lock, it is possible to determine whenthe slots of the various tumblers are aligned so that the combination ofthe lock can be discovered and access gained to the particular vault orsafe to which the lock is attached.

It is desirable, therefore, to provide some means for making the pointat which the fence strikes the tapered surface of the cam member whenthe dial shaft is moved between its axial positions, so that anunauthorized person cannot surreptitiously determine the combination ofthe particular lock.

It is, therefore, a general object of the present invention to provide acombination lock construction which overcomes the stated difiicultiesand disadvantages of the prior constructions and has improvedmanipulation-resistant qualities.

It is a further object of the present invention to provide a combinationlock construction having an axially tapered cam member arranged so thatthe lever tongue normally rides on a continuously circumferentiallyextending cam sunface spaced radially outwardly and axially from theentrance to the cam engagement or drive slot and in which contactbetween the cam and cam engagement or drive slot is masked.

It is still a further object of the present invention to provide acombination lock construction in which the fence connected to themasked-contact lever arm is normally held by the lever arm in a positionspaced from the outer peripheries of the tumblers.

It is another object of the present invention to provide a combinationlock construction in which separate contact concealment or falseengagement indicating means is provided for masking thepoint ofengagement of the lever or cam follower tongue with the tapered camsurface as the dial shaft is moved axially outwardly.

It is still another object of the present invention to provide acombination lock construction in which guide means is provided formaintaining the lever arm movable in a predetermined radial path orplane in reference to the cam member and dial shaft, thereby insuringthat the false engagement means will mask the engagement of the camfollower tongue with the tapered cam surface. 5

Finally it is an object of the present invention ,to provide acombination lock construction in which the cam member is formed from anon-metallic preferably plastic material, such as nylon, so that theengagement of the false engagement means and the engagement of the levertongue with the tapered cam surface, are mufiied and thereby, difli cultto discern.

These and other objects are accomplished by the parts, constructions,arrangements, combinations and subcombinations comprising the presentinvention, the nature of which is set forth in the following generalstatement, a preferred embodiment of whichillustrative of the best modein which applicants have contemplated applyingthe principlesis set forthin the following description and illustrated in the accompanyingdrawings, and which is particularly and distinctly pointed out and setforth in the appended claims forming a part hereof.

The improved manipulation-proof combination lock construction comprisingthe present invention may be stated generally as being included in acombination lock having the usual slotted tumblers rotatably mountedthrough lost motion driving connections on an axially movable dialshaft, with said look also having a tapered cam member mounted thereonworking in co-operation with the usual fence member for Withdrawing andextending the usual bolt member. The improvements to such a lock includea false engagement means separate from the fence member andengageableupon axial movement of the dial shaft for providing a falseengagement which can be confused with the engagement between the taperedcam member and fence member. This false engagement means may bepreferably mounted for engagement with the cam member upon axialmovement of the dial shaft and also preferably may include a series ofaxially spaced spring-pressed balls engageable by the cam, with the cammember also preferably being formed with a circumferentially extendinggroove to further increase the efliciency of the false engagement means.

It should be understood that this false engagement means is somethingcompletely separate from the fence member and its usual cam followertongue, and in its preferred form is something separately engageable bythe cam member independent of the engagement of the cam member with thefence member or any attachment thereto. Further, in order for the falseengagement means to most effectively mask the engagement of the cammember with the fence member, it is preferable for the cam member toengage at least part of the false engagement means normally at adifferent time than the time of engagement of the cam member with thefence member.

Finally, to provide for greater efliciency of the false en gagementmeans, it is preferable to mount the fence mem-' ber radially movable ina guide slot, requiring movement of the fence member and cam followertongue in a'predetermined plane perpendicular to the axis of the dialshaft, and also to form the cam member of av sound and 3 vibrationdeadening material, such as nylon, so that even the normal engagementbetween the cam member and metal fence member is not easily discernible.

By way of example, an embodiment of the combination lock construction ofthe present invention is illustrated in the accompanying drawingsforming a part hereof wherein like numerals indicate similar partsthroughout the several views and in which:

Fig l is a rear elevation of the combination lock constructron of thepresent invention with the rear cover plate thereof removed, the dialshaft and cam member in normal maximum forward position, the bolt memberin extended or locking position, and the cam follower tongue nding onthe continuous circumferential surface of the cam member maintaining thefence spaced upwardly from the outer peripheries of the tumblers;

Fig. 2, a front elevation of the rear cover plate in a position foldeddownwardly 180 from a position for assembly with the parts shown inFig.1;

3, a vertical section, part in elevation, looking in the direction ofthe arrows 3-3 in Fig. 1 with the rear cover plate in place;

Fig. 4, a front elevation of the combination lock constructionillustrating the dial and dial ring thereof;

Fig. 5, a horizontal section, part in elevation, through the dial shaftof the combination lock construction in the position illustrated in Fig.1, with the rear cover plate in place; 7

Fig. 6, a vertical section, part in elevation, looking in the directionof the arrows 66 in Fig.

Fig. 7, a view similar to Fig. l, with the dial shaft and cam membermoved axially to their rearmost position, and with the bolt member inextended position, the cam follower tongue engaged in the cam drivenotch, and the fence located in the tumbler notches;

Fig. 8, a view similar to Fig. 7, with the bolt member in retracted orunlocked position, the cam follower tongue engaged in the cam drivenotch, the fence located in the tumbler notches, and the cam memberrotated to boltretracted position;

, Fig. 9, a vertical section, part in elevation, looking in thedirection of the arrows 9--9 in Fig. 7, illustrating the various partsof the combination lock construction, when the dial member is pressedinwardly moving the dial shaft and cam member axially to their rearmostposition, with the cam follower tongue engaged in the cam drive notchand the fence located in the tumbler notches, and with the normalposition of the dial member being illustrated in dot-dash lines;

Fig. 10, a fragmentary rear elevation of the combinatio lockconstruction with the rear cover plate partially broken away, the dialshaft and the cam member in their maximum rearward position, the tumblernotches misaligned, and the fence riding on the outer peripheries of thetumblers, and with the first or rearmost positioned false engagementspring-loaded ball member engaged with the cam member tapered surfaceforwardly adjacent the cam member circumferential groove;

Fig. 11, a sectional view looking in the direction of the arrows 11-11in Fig. 10 and taken through the cam follower tongue and the firstspring-loaded ball member;

Fig. 12, a schematic view illustrating the position of the fence inreference to the outer peripheries of the tumblers, the cam followertongue in reference to the tapered cam surface, and the false engagementspring-loaded ball members in reference to'the circumferetnial grooveformed in the taperedcam surface, when the cam member is in the positionillustrated in Figs. 10 and 11;

Fig. 13, a sectional view similar to Fig. 11, but with the cam membermoved axially forward to a position wherein the first spring-loaded ballmember is engaged in the cam groove;

Fig. 14, a schematic view similar to Fig. 12 illustrating thepositioning of the various parts when the cam member is in the positionillustrated in Fig. 13;

Fig. 15, a view similar to Fig. 10, but with the cam member movedaxially forward and the second rearmost positioned false engagementspring-loaded ball member engaged in the cam groove;

Fig. 16, a sectional view looking in the direction of the arrows 1616 inFig. 15;

Fig. 17, a schematic view illustrating the position of the various partswhen the cam member is in the position illustrated in Figs. 15 and 16;

Fig. 18, a view similar to Fig. 15, but with the cam member movedaxially forward to a position wherein the third rearmost falseengagement spring-loaded ball member is engaged in the cam groove;

Fig. 19, a sectional view looking in the direction of the arrows 1919 inFig. 18;

Fig. 20, a schematic view illustrating the position of the various partswhen the cam member is in the position illustrated in Figs. 18 and 19;

Fig. 21, a view similar to Fig. 18, but with the cam member movedaxially forward to a position wherein the third spring-loaded ballmember has just left the cam groove and the fourth or forwardmostspring-loaded ball member has not yet engaged the cam groove, and thecam follower tongue has just engaged the tapered cam surface, but hasnot begun to raise the fence from the outer peripheries of the tumblers;

Fig. 22, a sectional view looking in the direction of the arrows 22-22in Fig. 21;

Fig. 23, a schematic view illustrating the position of the various partswhen the cam member is in the position illustrated in Figs. 21 and 22; I

Fig. 24, a view similar to Fig. 21, but with the cam member movedaxially forward to a position wherein the forwardmost spring-loaded ballmember has engaged in the cam groove, the cam follower tongue is engagedwith and has moved axially up the tapered cam surface, and the fence hasmoved to a position spaced upwardly from the outer peripheries of thetumblers;

Fig. 25, a sectional view looking in the direction of the arrows 25-25in Fig. 24;

Fig. 26, a schematic view illustrating the position of the various partswhen the cam member is in the position illustrated in Figs. 24 and 25;and

Fig. 27, a schematic view illustrating the position of the various partswhen the cam member has moved axially forward to its forwardmostposition or the position illustrated in Fig. 3. 1

The improved manipulation-proof combination lock construction of thepresent invention, as seen in Figs. 1 through 6, includes a case,generally indicated at 30, mounted on the inner face 31 of a door whichmay be the door of a safe or the like, and the lock may be used forstopping bolt work, not shown, in a usual manner. Much of the lockconstruction illustrated is of conventional construction, such as shown,for instance, in Abbott et al. Patent No. 1,956,304. The presentimprovements are incorporated in this conventional construction, andthese improvements comprising the present invention are hereinafterdiscussed in detail.

The front face 32 of case 30 is provided with an aperture 33 formedtherethrough providing a hollow cylindrical portion 34 therein, and thecase 30 is positioned on the door, so that the aperture 33 is in axialalignment with a somewhat smaller aperture 35 in the door. A dial ring36 is mounted on the outer face 37 of the door. The ring 36 is providedwith an outwardly opening annular recessed portion 38 which terminatescentrally in a hollow cylindrical portion 39, forming a centrallylocated aperture 40 in dial ring 36, and the aperture 40 is somewhatlarger in diameter than the aperture 35 in the door.

A hollow cylindrical tube 41 is located in aperture 33 formed bycylindrical portion 34. One end of tube 41 abuts the inner face 31 ofthe door, and the tube extends through aperture 33 and into the confinesof the case. The outer diameter of tube 41 is less than the diameter ofthe aperture 33 from the inner face 31 of .the door to the inner end ofthe cylindrical portion 34, and tube 41 then has a diameter slightlylarger than the aperture 33 from the inner end of portion 34 to theinner end of tube 41 extending in case 30. The inner diameters of tube41 are similarly formed of reduced and increased diameters, therebyforming the small-diameter portion 42 and largediameter portion 43.

An externally threaded dial operating spindle or shaft 44 extendsthrough dial ring aperture 40, door aperture 35 and the small and largediameter tube portions 42 and 43, with the inner end of spindle 44terminating at a point spaced inwardly from the inner end of tube 41. Adial member 45 is positioned partially received within the recessedportion 38 of dial ring 36 and is provided with a hub portion 46 ofslightly smaller diameter than the dial ring aperture 40 and of slightlylarger diameter than the door aperture 35. Hub portion 46 is partiallytelescoped in the dial ring aperture 40.

Dial member 45 is provided on its outer face with the conventionaloperating knob 47, which is of the usual generally cylindrical knurledconstruction. Further, as is conventional, the dial ring 36 may haveinscribed thereon one hundred equally spaced division lines 48, witheach tenth of these division lines being numbered providing a dialnumbering from ten to one hundred, as best seen in Fig. 4. Also, as bestseen in Fig. 4, a single preferably vertically-extending mark or arrow49 is formed inscribed on the dial ring 36 above knob 47, with this markbeing utilized in conjunction with rotation of the dial for operatingthe combination of the lock.

An improved cam member, generally indicated at 50, is mounted on theinner end of spindle 44, including generally hollow cylindrical head andtube portions 51 and 52. Portions 51 and 52 are internally threaded andthe spindle 44 is threadably received within the tube portion 52. Cammember 50 is secured on spindle 44 by an L-shaped key member 53 receivedin keyways formed in the cam member 50 and spindle 44, so that the headportion 51 is retained abutting the inner end of the tube 41.

Further, when thus positioned, the tube portion 52 is rotatably receivedwithin the large-diameter tube portion 43, so that tube portion 43 formsan internal bearing surface. Cam member 50 is preferably formed from anonmetallic plastic material, such as nylon, the advantages of which,for use in the present invention, will be hereinafter described.

A compression spring 54 is positioned surrounding the hollow cylindricalportion 39 of dial ring 36 and also surrounding the hub portion 46 ofdial member 45, so that oneend of said spring abuts the inner face 45aof dial member 45 and the other end of said spring abuts the recessedportion 38 of dial ring 36. Thus, dial member 45 may be selectivelypressed inwardly toward the outer face 37 of the door and into the dialring recessed portion 38, with the result that spring 54 is compressedand spindle 44 moves axially rearwardly, moving the cam member 50rearwardly in reference to tube 41, so that cam member 50 approaches therear cover plate 55 of case 30. Spring 54, however, normally urges thedial 45, spindle 44 and cam member 50 to their normal outward or forwardposition, as illustrated in Fig. 5.

A series of preferably three tumbler wheels 56, 57 and 58 is rotatablymounted on the large-diameter tube portion 43, with the forwardmost ofsaid tumblers or tumbler 58 abutting the inner or rearward end of thecase cylindrical portion 34. Thus, an outer bearing surface is formed onthe tube portion 43. Tumblers 56, 57 and 58 are of conventionalconstruction and each includes a pair of spaced outer ring disc membersadjustably engaged with a hub or center member, and each is providedwith registering notches or slots formed in the outer ring disc members.These notches are preferably formed at an angle to a radial line on thetumblers, as best seen in Fig. 1, for a purpose to be hereinafterdescribed.

A pin or projection 59 is formed on the front or for ward face of cammember 50 and this pin is engageable with a preferably nylon lever 56ajournalled on the tube 41, with the other side of the lever 56a being inposition to abut one end of a segmental flange formed on the centermember of tumbler 56. Pin 59 is only engageable with this nylon lever56a upon rotation of cam member 50, when the cam member is in itsforwardmost or normal position, as illustrated in Fig. 5, and isdisengaged therefrom when the dial member 48 is pressed inwardly movingthe cam member 50 to its rearward position.

Thus, a lost-motion drive is provided between the cam member 50 and thetumbler 56. A similar lost-motion drive is provided between each set ofadjacent tumblers, that is to say, between tumblers 56 and 57 andbetween tumblers 57 and 58, and in each case, the drive includes a pinon the tumbler, a preferably nylon lever journalled on the tube 41 and asegmental flange on the next adjacent tumbler.

Further, rotation of the cam member 50 by rotating the dial member 45causes rotation of the tumblers 56, 57 and 58 only when the cam member50 is in its normal or forward position, and when the dial member 45 ispressed inwardly moving the cam member 50 axially to its rearwardposition, the driving connection between cam member 50 and the tumblers56, 57 and 58 is interrupted, so that further rotation of cam member 50will not cause rotation of the tumblers.

The improved cam head portion 51 is provided with an axially preferablyuniformly tapered outer circumferential surface 60, which tapersdownwardly forwardly, that is to say, the rearward face of portion 51 orthe face thereof nearest the rear cover plate 55, is of larger diameterthan the forward face or the face thereof nearest the tumbler 56.Surface 60 is provided with a continuous circumferentially extendinggroove 61 formed therein spaced from the rearward face of head portion51.

A conventional laterally-extending bolt member 62 is slidably receivedthrough the side wall 63 of case 30 and is mounted for lateralreciprocation in the conventional slides or guideways 64. Alaterally-extending operating lever 65 is pivotally connected to boltmember 62 by, means of the pivot screw 66.

Lever 65 includes a laterally-extending operating arm 67 and adownwardly-extending cam follower tongue 68.- Tongue 68 normally restson and bears against the outer circumferential cam surface 60 overlyinggroove 61 when cam member 50 is in its normal forward position, as illustrated in Fig. l. A spring 69 is engaged over the pivot screw 66 and theoperating arm 67, urging the operating arm downwardly, and consequentlyurging the cam follower tongue 68 against the cam member 50.

Cam follower tongue 68 has a thickness greater than the width of groove61 formed in the cam surface 60, so that when cam 50 is in its normalforward position, tongue 68 spans the width of groove 61, with the backsurface of tongue 68 or the surface thereof nearest the rear cover plate55 preferably positioned substantially in vertical alignment with theback surface of cam member 50, as best seen in Fig. 3.

Further, the cam head portion 51 is provided with a radially-extendinglever operating notch or slot 70, preferably opening forwardly of headportion 51 and radially outwardly through the cam surface 60, with notch70 extending from the forward face of head portion 51 rearwardly to apoint spaced forwardly from the cam circumferential groove 61 and theforward face of tongue 68.

Notch 70 is positioned such that when the dial member 45 is pressedinwardly toward the outer face 37 of the door, thereby moving thespindle 44 and the cam member 50 axially rearwardly toward the backcover plate 55, the cam follower tongue 68 will overlie thecircumferential area within which notch 70 is formed. Thus, when cammember 50 is rotatedto a position in which notch 70 underlies tongue 68,tongue 68 may be received therein provided certain other conditionsexist, as will he hereinafter described. As illustrated in Figs. 1, 3and 6, the lower end 71 of tongue 68 is tapered both laterally andforwardly in a generally tangential plane to the outer circumferentialtapered cam surface 60, so that when cam member 50 is in its normalforward position and the tongue 68 bears against the cam surface 60spanning the groove 61 formed therein, the lower end 71 will generallyfollow the contour of the tapered surface 60, as illustrated in Fig. 3.

The case 30 is provided with a lever arm guide yoke, generally indicatedat 72, mounted partially on the case top wall 73 and partially on therear cover plate 55. The top wall portion 74 of yoke 72 is preferablyformed of nylon and is positioned overlying the tumblers 56, 57 and 58and overlying a portion of the cam head portion 51, so that the rearwardend of yoke wall portion 74 is spaced forwardly from the rear coverplate 55. The rear cover plate portion 75 of yoke 72 is mounted on theforward or inner face of rear cover plate 55 and extends forwardly toapproximately the plane of the rear face of cam member 50 and is therebyspaced rearwardly from the rearward end of wall portion 74 providing alever operating arm guide slot 76.

Guide slot 76 is in alignment with the operating arm 67 overlying aportion of the cam follower tongue 68 and receiving a portion of theoperating arm 67 therein when the cam 50 is in its normal forwardposition and the cam follower tongue 68 is riding on the tapered surface60 spanning the groove 61. The width of guide slot 76 is slightlygreater than the width of operating arm 67, so that the operating arm isguided in its upward and downward travel when the cam member 50 is movedbetween its normally forward and rearward position, with the lowerrearward edge of yoke case wall portion 74 being formed in an arcuateconfiguration for easier entrance of operating arm 67.

A fence 77 is mounted on the rout face of the lever operating arm 67 andextends forwardly normally overlying and spaced from the tumbler 56, 57and 58 when the cam member 50 is in its normal forward position, asillustrated in Figs. 1 and 3. When cam member 58 is moved to itsrearmost position, and the notches formed in the tumblers are notaligned, fence 77 rides on and bears against the outer peripheries ofthe tumblers, maintaining the cam follower tongue 68 spaced upwardlyfrom the tapered cam surface 60, and cam notch 7%, as illustrated inFig. 10, but when the notches of the tumblers are in alignment with thefence 77, the fence may be received therein permitting the cam followertongue 68 to be received in the cam notch 70 to withdraw the bolt 62 ina conventional manner, the operation of which will be hereinafter morefully described.

The case top wall 73 is provided with a downwardly projecting abutmentportion 78, which portion prevents the lever operating arm 67 andconsequently the bolt member 62 from moving laterally when the cammember 50 is in its normal forward position and the cam follower tongue68 is riding on the tapered surface 60 spanning the groove 61, or whenthe cam member 50 is in its rearward position, but the fence 77 isriding on the outer peripheries of the tumblers 56, 57 and 58. The rearcover plate 55 is provided with the conventional aperture 79 formedtherein so that a key used for changing combinations may be insertedtherethrough without removal of the rear cover plate 55. The combinationof the lock may be changed by rotating the outer ring disc members ofthe tumblers about the center members thereof in the conventional.manner.

A false engagement ball cage 89 is mounted on the inner or front face ofthe rear cover plate 55 and is provided with preferably four spacedspring-loaded or springpresscd balls 81, 82, 83 and 84 mounted therein.As illustrated in Fig. 9, each of the spring-loaded balls is mounted inthe cage 80 in a conventional manner of mounting spring-loaded balls, sothat each ball extend; a maximum predetermined distance from face 801:of cage and is normally resiliently urged to such extended position by ausual spring 84a. Thus, as shown in Fig. 9, ball 84 may be depressedinto ball cage 80 by an outside force, until the top edge of ball 84 isin alignment with cage surface 80a, by compressing spring 84a, but ball84 may not be urged to extend from cage surface 80a beyond apredetermined distance, as shown.

Cage 80 is formed in a generally arcuate configuration and is positionedso that the spring-loaded balls engage the cam tapered surface 60 andthe groove 61 formed therein as the cam member 50 is moved between itsnor mal forward and rearward positions and vice versa. Thus, the contourof the ball cage 80 and the positioning of the spring-loaded ballstherein positions these balls at circumferentially spaced points along aportion of the circumference of the cam 5%.

These spring-loaded balls are further positioned in ball cage 80 atunequal distances from the front face of the rear cover plate 55, thatis, axially spaced in reference to the longitudinal axis of cam member50, so that ball 81 is nearest the front face of rear cover plate 55,ball 84 is farthest from rear cover plate 55 and balls 82 and 83 are atspaced distances therebetween. Still further, these spring-loaded ballsare positioned at an axial position with reference to the longitudinalaxis of cam member 50 and with the axial position of cam follower tongue68 such that the first engagement of tongue 68 with the cam taperedsurface 60, as the cam member 50 is moved from its rearward positionaxially toward its normal forward position, will occur at some pointeither during the engagement of one of these spring-loaded balls in thecam groove 61 or immediately after one of the balls has disengaged fromgroove 61 and before the next adjacent ball engages with groove 61.

In the particular embodiment illustrated in the drawings, thepositioning of the spring-loaded balls in reference to the cam member 50and the movement thereof, is such that upon moving the cam memberaxially between its rearward position and its normal forward position,the engagement of the cam follower tongue 68 with the cam taperedsurface 60, occurs immediately after the third spring-loaded ball 83 hasdisengaged from or snapped out of the cam groove 61 and immediatelyprior to the engagement or snapping in of the fourth springloaded ball84 into said groove.

It should be understood, however, that the engagement of the camfollower tongue 68, with the cam tapered surface 60, may be arranged tooccur at any desired time, that is, prior to the engagement of any ofthe springloaded balls with the cam groove 61, simultaneous with theengagement of any one ball with said groove, intermediate thedisengagement of one ball and the engagement of the next ball with saidgroove, or after the last ball has disengaged from said groove, withoutdeparting from the principles of the present invention.

It is preferred, however, that the engagement of the tongue with the camtapered surface should occur simultaneous with the engagement of one ofthe balls with the groove or intermediate the disengagement of one balland the engagement of the next ball with the groove. Further, in theevent that the production tolerances become prohibitive or it is desiredto minimize production costs, it is possible with the use of a pluralityof spring-loaded balls to allow the positioning of these balls inreference to the cam tapered surface to vary over a wider range, sinceas described above, as long as the engagement of the cam follower tongue68 with the cam tapered sure face 60 occurs in relatively closeproximity to the engagement of any one of the spring-loaded balls withthe cam groove 61, the advantages of the present invention will beprovided.

In the general operation of the combination lock -illustrated in thedrawings, which general operation is conventional to certain priorconstructions of locks, when the lock is in locked position with thebolt member 62 extended, the notches of the tumblers 56, 57 and 58 arein misaligned position, as illustrated in Fig. 1. Further, cam member 50is in its forward position and the cam follower tongue 68, on theoperating lever 65, is resting on the tapered cam surface 60, spanningand overlying the cam groove 61. Finally, the cam follower tongue 68retains the fence 77 spaced upwardly from the outer peripheries of thetumblers 56, 57 and 58.

The dial member 45 is turned alternately in opposite directions to setthe predetermined combination of the lock by means of the knob 47 in theconventional manner. When the combination has been properly set, thenotches of tumblers 56, 57 and 58 are in aligned position, with theopenings of said notches underlying the fence 77.

The dial member 45 is then pressed inwardly against the pressure ofspring 54, and thereby moves the spindle 44 rearwardly, moving the cammember 50 to its rearward position. When the cam is in this position,the cam pin 59 is disengaged from any driving connection between cam 50and the first tumbler 56, so that any further rotation of dial member 45will not rotate any of the tumblers and change their positions.

When dial member 45 is pressed inwardly, the cam follower tongue 68moves down the tapered cam surface 60, so that when cam member 50 is inits rearward position, the cam follower tongue 68 is in circumferentialalignment with cam notch 70. During this rearward movement of cam member50, fence 77 moves downwardly into the opening portion of the notches intumblers 56, 57 and 58, and if cam notch 70 is in radial alignment withcam follower tongue 68, the cam follower tongue will engage partiallyinto cam notch 70, otherwise cam follower tongue 68 will rest againstthe tapered cam surface 60 in circumferential alignment with cam notch 70.

With dial member 45 retained in its inwardly-pressed position,maintaining the cam member 50 in its rearward position, the dial member45 is rotated in a clockwise direction looking at the face of the dialmember or in a counterclockwise direction looking at the rear of thecase 30, as shown in Figs. 7 and 8. This rotation of dial member 45rotates cam member 50 and if cam notch 70 is not in radial alignmentwith cam follower tongue 68, when cam member 50 is rotated to a positionfor such radial alignment between said notch and tongue, said tonguewill then engage partially into said notch, in the position illustratedin Fig. 7.

Continued rotation of cam member 50 causes the cam follower tongue 68 tofurther engage in cam notch 70 and causes cam member 50 to moveoperating lever 65 and consequently bolt member 62 from locked orboltextended position to unlocked or bolt-retracted position, saidunlocked position being illustrated in Fig. 8. The resiliency of spring69 urging operating lever 65 downwardly or urging it to rotate in acounterclockwise direction, as seen in Figs. 7 and 8, around the pivotscrew 66, causes the cam follower tongue 68 and the fence 77 to engagein the cam and tumbler notches, respectively, when cam member 50 isrotated to unlocked position.

Since fence 77 is mounted on the end portion of operating lever 65 andsince operating lever 65 is rotating around pivot screw 66 during theunlocking operation, fence 77 must move downwardly in an arcuate pathdetermined by the constant radial distance of fence 77 from' pivot screw66. Thus, with the notches in tumblers 56, 57 and 58 being positionedopening and extending at an angle to a radial line of said tumblers, thefence 77 is permitted to easily and conveniently enter ,or leave saidnotches.

In relocking the lock, the dial member 45 is merely rotated in acounterclockwise direction, looking at the face-of said dial, .or aclockwise direction, looking-at the rear of case 30, as viewed in Figs.7 and 8, and such row tion rotates cam member 50, causing said cammember to move operating lever 65 and bolt member 62 to the right, asseen in Figs. 7 and 8. This rotation is con tinued until cam followertongue 68 is disengaged from cam notch 70, at which time, spring 54urges dial member 45 and cam 50 to their normal forward positions,

present invention, to determine the combination and unlock the lock bycarrying out procedures of manipulation that have been evolved, furtherprovided that the lower longitudinal face of fence 77 is at a slightangle to the longitudinal axis of tumblers 56, 57 and 58, or that theouter peripheries of the tumblers are slightly misaligned or havedifferent dimensions in reference to each other, Such conditions mayexist in almost all combination locks that have been built in massproduction due to variations in the size and assembly of parts. Asbefore stated, these slight errors are unavoidable if a combination lockis to be mass produced, even though the most modern production equipmentand controls are used.

Assuming, for purposes of description, that the lower longitudinal faceof fence 77 angles slightly upwardly from its point of connection tooperating arm 67 on the operating lever 65 and in reference to thelongitudinal I axis of tumblers 56, 57 and 58, a person attempting tomanipulate the lock would start by pressing the dial member 45 inwardlycausing the cam member 50 to move to its rearward position. Themanipulator would then allow the dial member 45 to move outwardly and byuse of the sense of feel and conventional depth gauges, determine atwhat point in the outward movement of dial member 45 the cam followertongue 68 engaged with the tapered cam surface 60.

The manipulator would then rotate the dial member 45 predeterminedincrements repeating the above measuring operation at each positionuntil a point was found when the cam follower tongue 68 engaged thetapered cam surface 60 at a point earlier than the first measurementtaken, that is, when the cam follower tongue 68 engaged at a lower pointon the tapered cam surface 60. This occurrence would indicate that atthat position, the fence 77 is engaged with the notch of tumbler 56,which engagement would permit the fence 77 and thus, the cam followertongue 68 to move downwardly a greater distance when the cam member 50is moved to its rearward position by pressing in dial member 45. In thisway, the position of the notch in tumbler 56 would be determined.

It is apparent that, with fence 77 angling slightly upwardly inreference to the longitudinal axis of tumblers 56, 57 and 58, when thenotches of both tumblers 56 and 57 are in alignment with fence 77, thecam follower tongue 68 would be permitted to move downwardly a stillgreater distance when the cam member 50 is moved to its rearwardposition by pressing in the dial member 45. Further this occurrencecould be determined by a manipulator by measuring the point at which thecam follower tongue 68 engaged the tapered cam surface 60, as the dialmember 45 was permitted to move outwardly moving the cam member 50toward its forward position. Thus, in this manner, the properpositioning of each of the tumblers 56, 57 and 58 for alignment of thenotches thereof with fence 77 could be determined, and a skilledmanipulator can ultimately manipulate the lock to place it in unlockedposition.

However, the improvements of the present invention hide or mask thepoint at which the cam follower tongue 68 engages the tapered camsurface 60 when cam member 50 is moved from its rearward to its normalforward position; This masking is accomplished by the arrange ment, orconstruction, configuration and composition of cam member 50, the falseengagement means, and the guide yoke 72. In the present embodiment thefalse engagement means is in the form of ball cage 80, and springloaded,balls 81, 82, 83 and 84 and the yoke 72 guide the upward and downwardmovement of operating arm 65 and consequently cam follower tongue 68.

It should be understood that the false engagement means can includemembers other than balls mounted in relation to the dial member 45,spindle 44 or cam member 50, which produce a definite feel of engagementwhen the cam member 50 is moved from its rearward to its normal forwardposition, and which mask or make it impossible to identify the point atwhich the cam follower tongue 68 engages the cam member 50, therebymaking manipulation of the lock impossible. It is preferred, however,that the false engagement means he in the form of the spring-loadedballs 81, 82, 83 and 84 mounted in the ball cage 80 and bearing againstthe tapered cam surface 60, as illustrated in the drawings. One of theprincipal advantages of using spring-loaded balls is that it isrelatively easy to maintain close tolerances in the positioning of theseballs in reference to the cam member 50, both radially andlongitudinally of the cam member, in mass production, thereby resultingin reduced production costs as compared to the use of other types offalse engagement means.

Referring to Figs. through 27, the positions of the various parts of thelock are shown in sequence as the dial member 45 and consequently thecam member 50 are moved from their rearward positions to their normalforward positions. Certain pertinent positions are shown in each case ina view looking at the back of case 38 with the rear cover plate 55broken away, in section showing the position of the fence 77 in relationto the outer peripheries of the tumblers 56, 57 and 58, cam followertongue 68, earn 50 and various sections through the ball cage 80, and adiagrammatic View showing the relation of the outer peripheries of thetumblers 56, 57 and 58, fence 77 and cam follower tongue 68, the cammember 54) and the spring-loaded balls 81, 82, 83 and 84.

.As illustrated in Figs. 10, 11 and 12, the dial member 45 has beenpressed inwardly placing the cam member 50 at its maximum rearwardposition, so that the fence 77 is resting on the outer peripheries ofthe tumblers 56, 57 and 58, thereby retaining the cam follower tongue 68spaced upwardly from the tapered cam surface 60 and overlying thecircumferential area of cam 50 having the cam notch 70 formed therein.Further, the first or the rearmost spring-loaded ball 81 is in aposition just engaging the tapered cam surface 60 forwardly of the camgroove 61, while the other spring-loaded balls 82, 83 and 84 areforwardly of ball 81 and are therefore not as yet engaged with cammember 59.

In Figs. 13 and 14, the cam member 59 is shown moved forwardly to apoint where the first or rearmost spring-loaded ball 81 has snapped intoor engaged with the cam groove 61. The fence 77 is still resting on theouter peripheries of tumblers 56, 57 and 58 retaining the cam followertongue 68 spaced upwardly from the tapered cam surface 60. The secondspring-loaded ball 82 in this position has started to engage the taperedcam surface 60, while the third and fourth spring-loaded balls 83 and 84are still spaced forwardly and not in engagement with said tapered camsurface.

As shown in Figs. 15, 16 and 17, the cam member 50 has been movedforwardly until the second spring-loaded ball 82 has snapped" into orengaged the cam groove 61 and the first spring-loaded ball 81 has movedout of engagement with cam groove 61 and is resting on the tapered camsurface 60 rearwardly of said cam groove. The fence 77 is still restingon the outer peripheries of the. tumblers 56, 57 and 58 retaining thecam follower tongue '68 spacedupwardlyfrom the tapered cam sur- 1 2 face60, while, the third spring-loaded ball 83* is just. engaging with thetapered cam surface 60 forwardly ofthe cam groove 61 and the fourthspring-loaded ball 84 is still out of engagement with any portion of cam50.

As cam 50 is moved forwardly, another increment, as illustrated in Figs.18, 19 and 20, the third spring-loaded ball 83 has snapped into or isengaged in the cam groove 61, while the first and second spring-loadedballs 81 and 82 are riding on the tapered cam surface 60 rear wardly ofsaid groove. Further, fence 77 is still resting on the outer peripheriesof tumblers 56, 57 and 58 retaining the cam follower tongue 68 spacedupwardly from the tapered cam surface 60, with the fourth spring-loadedball 84 just engaged with the tapered cam surface 60 forwardly of thecam groove 61. I

As illustrated in Figs. 21, 22 and 23, the cam member 58 has been movedforwardly until the third springloaded ball 83 has begun to move out ofcam groove 61 and the first and second spring-loaded balls 81 and 82 arebearing against the tapered cam surface 60 rear wardly of cam groove 61,while the fourth spring-loaded ball 84 has not as yet snapped into orfully engaged with cam groove 61. In this position, fence 77 is stillresting on the outer peripheries of tumblers 56, 57 and 58, but the camfollower tongue 68 has just engaged the tapered cam surface, 60 at apoint forwardly of and partially overlying the tapered cam groove 61.

As cam member 50 is moved further forwardly, as illustrated in Figs. 24,25 and 26, the fourth spring-loaded ball 84 snaps into or engages withcam groove 61, while the first three spring-loaded balls 81, 82 and 83are bearing against, the tapered cam surface 60 rearwardly of cam groove61. Further, in this position, the cam follower tongue 68 has begun tomove upwardly on the tapered cam surface 68 and is resting thereon,thereby raising the fence 77 from the outer peripheries of turnblers 56,5'7 and 58.

Finally, as illustrated in Figs. 1, 3 and 27, earn member 50 has movedto its normal forward position, with cam follower tongue 68 resting onthe tapered cam surface 60 spanning the cam groove 61 and therebyretaining fence 77 spaced upwardly from the outer peripheries oftumblers 56, 57 and 58. The second, third and fourth spring-loaded balls82, 83 and 84 are engaged with the tapered cam surface 60 rearwardly ofcam groove 61, with the first or rearmost spring-loaded ball 81 engagedslightly over the back or rearward edge of cam member 50.

Thus, the false engagement means, shown in the present embodiment of theform of spring-loaded balls 81, 82, 83 and 84 mounted in ball cage 88,prevents an unau thorized person attempting to manipulate the lock fromdetermining when the cam follower tongue 68 engages the tapered camsurface 60, and therefore such manipulator is prevented from determiningthe position of the notches in the tumblers 56, 57 and 58. Although, asbefore stated, other forms of false engagement means may be usedengageable with any of the dial member 45, spindle 44 or cam member 50,it is preferred to use resilient means such as the spring-loaded balls81, 82, 83 and 84 in combination with a cam groove 61 formed in atapered cam surface 60, since not only do these spring-loadedballscreate a definite feel of engagement when they engage the tapered camsurface 60 and snap into cam groove 61, but also this snapping of thesespring-loaded balls into the cam groove causes a definite jump in theinward movement of cam member 50, spindle 44 and dial member 45, so thatit is impossible to accurately measure definite distances of partialinward movement of the dial member.

The guide yoke 72. serves the purpose of guiding operating lever 65 inits upward and downward movement in a definite path and consequently thecam follower tongue 68, is so guided. The spring-loaded balls 81, 82, 83and 84 thus may be set .at predetermined positions in rela,-.

tion to cam follower tongue 68, so that the engagement of cam followertongue 68 with the tapered cam surface 60 will always occur at somepoint intermediate the engagement of adjacent spring-loaded balls orsimultaneous with the engagement of a particular spring-loaded ball. Inany such event, the positioning of the spring-loaded balls in relationto the upward and downward movement of the cam follower tongue may beset at a predetermined relationship so that the cam follower tongue willengage the tapered cam surface at some point intermediate the engagementof the first spring-loaded ball and the disengagement of the lastspring-loaded ball with the cam groove, despite the positioning of thetumbler notches, the angularity of the fence, and the uniformity ornonuniformity of the outer peripheries of the tumblers. The wall portion74 of guide yoke 72 is preferably formed from a non-metallic plasticmaterial such as nylon, to reduce wear and reduce the noise of operationwhile at the same time the self-lubricating qualities of nylon areutilized.

The cam member 50 is also preferably formed of a non-metallic plasticmaterial, such as nylon, again because of the wearing and also the soundand feel deadening qualities of nylon. Although metallic spring-loadedballs 81,82, 83 and 84 are used snapping in and out of the cam groove61, and although the cam follower tongue 68'rests on the tapered camsurface 60 during the' se'tting of the combination of the lock, a nyloncam, because 'of its excellent wearing qualities, will far outlast the"usefulness of the metallic parts in the lock. Also, withthe' use of anylon cam member 50, the engagement of' anything with the tapered camsurface 60, such as the metal cam follower tongue 68, is much moredifficult to discern, due to the sound and feel deadening qualities ofnylon. I

Although it is preferred that the tapered cam surface 60 of'cam member50 have a uniform taper of about the degree of taper shown, it should beunderstood that other degrees of taper and non-uniform tapers may beused without departing from the principles of the present invention.

Finally, it should be understood that although forming the-cam member 50from material, such as nylon, provides certain advantages as pointed outabove, this cam member may be formed of other materials, includingmetal, and many of the advantages and improvements of the presentinvention including manipulation-proofness would still be provided.

In the foregoing description, certain terms have been usedfor brevity,clearness and understanding, but no unnecessary limitations are to beimplied therefrom, because such words are used for descriptive purposesherein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated anddescribed herein are by way of example and the scope of the presentinvention is not limited to the exact details of construction shown.

' Having now described the invention, the construction, operation anduse of a preferred embodiment thereof, the advantageous new and usefulresults obtained thereby, the new and useful construction and reasonablemechanical equivalents thereof, obvious to those skilled in the art, areset forth in the appended claims.

, We claim:

1. In a combination lock of the kind having a housing, a locking membermovably mounted on said housing, an elongated, manually-rotatable, dialshaft extending into 'said housing, longitudinally movable betweennormal and second positions, a'disk-like cam secured to said shaftwithin 'saidhousing for rotation and longitudinal movement with saidshaft, said cam having a gate in the periphery thereof, a movable fenceassociated with said locking member for controlling movement thereof,said fence being 'formedto initially engage the cam during movementof'the earn from said second to normal position and to interlock withthe gate of said cam when the latter is in said second longitudinalposition and is rotated to a predetermined position with respect to saidfence, whereby continued rotation of said cam in one direction shiftssaid fence and said locking member to an unlocked position, the wallsdefining said gate being formed to move said fence to a positionreleased from said cam when said cam is rotated in the oppositedirection, a plurality of tumblers interconnected by lost motion drivingconnections and being operably mounted within said housing and about theaxis of said shaft, and a lost motion driving connection between saidcam and one of said tumblers, said tumblers blocking movement of saidfence from said released position except when they are shifted to apredetermined set position in which said fence is permitted to move to aposition interlocked with said cam; the improvement of which comprisesperipheral groove means formed circumferentially in the cam, andresilient means spaced longitudinally with respect to the dial shaft andcircumferentially with respect to the cam respectively sequentiallyengaging the cam and cam groove means as the dial shaft is movedlongitudinally from second to normal position thereby indicating falseengagements with the cam as the cam carried by the dial shaft is shiftedlongitudinally from said second to normal position which masks theinitial engagement of the fence with the cam.

2. In a combination lock of the kind having a case, a longitudinallymovable spindle rotatably mounted extending partially into the case,dial means mounted on the spindle outside of the case, generallycylindrical cam means having a drive notch formed therein mounted on thespindle within the case, said dial and cam means being rotatable andlongitudinally movable with the spindle, a series of tumbler wheelshaving outwardly opening notches formed therein rotatably mounted on thespindle and interconnected in lost motion driving connection to eachother and to the cam means when the spindle is in its normal position oflongitudinal movement, said cam means driving connection beinginterrupted when the spindle is moved from its normal to a secondlongitudinal position, movable bolt means having a cam follower tongueand a fence operably connected thereto, the fence being received in thetumbler wheel notches when said notches are aligned at a predeterminedposition and permitting the cam follower tongue to engage the cam meansdrive notch when the spindle is moved from its normal to said secondlongitudinal position and rotated thereby retracting the bolt means, thefence resting on the'tumbler wheels maintaining the cam follower tonguedisengaged from the cam means when the tumbler wheel slots are notaligned at said predetermined position and when the spindle is thenmoved from its normal to said second longitudinal position, and the camfollower tongue resting on the cam means and maintaining the fencespaced from the tumbler Wheels when the spindle is in its normalposition; the improvements including a tapered outer peripheral surfaceformed on the cam means, the cam follower tongue being engaged by saidtapered surface when the spindle and cam means are moved from saidsecond longitudinal position to normal position and when the tumblerwheel notches are not aligned at said predetermined position, the camfollower tongue initially engaging said tapered surface after partialmovement of the cam means from second to normal position and remainingengaged with said surface after such initial engagement and during theremaining movement of the cam means to normal position, false engagementmeans including engageable elements mounted on the lock independent ofthe cam follower tongue and independent of said engagement of the camfollower tongue with the cam means, certain of said false engagementelements being operably connected to and movable with the movablespindle, and at least certain of said engageable elements moving topositions of engagement with each other normally at a different timethan said engagement of the cam follower tongue with the cam means uponlongitudinal movement of the spindle, Whereby separate false engagementindications are given establishing confusion with the indication of saidengagement of the cam follower tongue with the cam means.

3. The combination lock construction defined in claim 2 in which thefalse engagement means includes elements mounted for engagement with thecam means normally at a different time than said engagement of the camfollower tongue with the cam means upon longitudinal movement of thespindle and cam means.

4. The combination lock construction defined in claim 2 in which thefalse engagement means includes resilient means mounted for engagementwith the cam means normally at a different time than said engagement ofthe cam follower tongue with the cam means upon longitudinal movement ofthe spindle and cam means.

5. In a combination lock of the kind having a case, a longitudinallymovable spindle rotatably mounted extending partially into the case,dial means mounted on the spindle outside of the case, generallycylindrical cam means having a drive notch formed therein mounted on thespindle within the case, said dial and cam means being rotatable andlongitudinally movable with the spindle, a series of tumbler wheelshaving outwardly opening notches formed therein rotatably mounted on thespindle and interconnected in lost motion driving connection to eachother and to the cam means when the spindle is in its normal position oflongitudinal movement, said cam means driving connection beinginterrupted when the spindle is moved from its normal to a secondlongitudinal position, movable bolt means having a cam follower tongueand a fence operably connected thereto, the fence being received in thetumbler wheel notches when said notches are aligned at a predeterminedposition and permitting the cam follower tongue to engage the cam meansdrive notch when the spindle is moved from its normal to said secondlongitudinal position and rotated thereby retracting the bolt means, thefence resting on the tumbler wheels maintaining the cam follower tonguedisengaged from the cam means when the tumbler wheel slots are notaligned at said predetermined position and when the spindle is thenmoved from its normal to said second longitudinal position, and the camfollower tongue resting on the cam means and maintaining the fencespaced from the tumbler Wheels when the spindle is in its normalposition; the improvements including a tapered outer peripheral surfaceformed on the cam means, the cam follower tongue-being engaged by saidtapered surface when the spindle and cam means are moved from saidsecond longitudinal position to normal position and when the tumblerwheel notches are not aligned at said predetermined position, the camfollower tongue initially engaging said tapered surface after partialmovement of the cam means from second to normal position and remainingengaged with said surface after such initial engagement and during theremaining movement of the cam means to normal position, and falseengagement means independent of the cam follower tongue including aseries of longitudinally spaced resiliently pressed members engageablewith the cam means at longitudinally spaced in-. tervals as the cammeans is moved from its second longitudinal position to its normalposition.

6. The combination lock construction as defined in claim 5 in which theresiliently pressed members are spring-pressed balls mounted on thecase.

i 7. In a combination lock of the kind having a case, a longitudinallymovable spindle rotatably mounted extending partially into the case,dial means mounted on the spindle outside of the case, generallycylindrical cam means having a drive notch formed therein mounted on thespindle within the case, said dial and cam means being rotatable andlongitudinally movable with the spindle, a series of tumbler wheelshaving outwardly opening notches formed therein rotatably mounted on thespindle and interconnected in lost motion driving connection to eachother and to the cam means when the spindle is in its normal position oflongitudinal movement, said cam means driving connection beinginterrupted when the spindle is moved from its normal to a secondlongitudinal position, movable bolt means having a cam follower tongueand a fence operably connected thereto, the fence being received in thetumbler wheel notches when said notches are aligned at a predeterminedposition and permitting the cam follower tongue to engage the cam meansdrive notch when the spindle is moved from its normal to said secondlongitudinalposition and rotated thereby retracting the bolt means, thefence resting on the tumbler wheels maintaining the cam follower tonguedisengaged from the cam means when the tumbler wheel slots are notaligned at said predetermined position and when the spindle is thenmoved from its normal to said second longitudinal position, and the camfollower tongue resting on the cam means and maintaining the fencespaced from the tumbler wheels when the spindle is in its normal sition;the improvements including a tapered outer periph-,- eral surface formedon the cam means, the cam follower tongue being engaged by said taperedsurface when the spindle and cam means are moved from said secondlongitudinal position to normal position and when the tumbler wheelnotches are not aligned at said predetermined po,- sition, the camfollower tongue initially engaging said tapered Surface after partialmovement of the cam means from second to normal position and remainingengaged with said surface after such initial engagement and during theremaining movement of the cam means to normal sition, false engagementmeans independent of the cam follower tongue and independent of saidengagement of the cam follower tongue with the cam means, said falseengagement means including a circumferentially extending groove formedin the tapered cam surface of the cam spaced axially from the ends ofthe cam means and opens ing radially outwardly of the tapered outerperipheral surface, and said false engagement means also including resilient means mounted for engagement with the groove and tapered camsurface as the cam means is moved from its second longitudinal positionto its normal position, whereby the false engagement means providesseparate engagement indications establishing confusion with theindication of engagement of the cam follower tongue with the cam means.

8. In a combination lock of the kind having a case, a longitudinallymovable spindle rotatably mounted ens tending partially into the case,dial means mounted on the spindle outside of the case, generallycylindrical cam means having a drive notch formed therein mounted on thespindle within the case, said dial and cam means being rotatable andlongitudinally movable with the spindle, a series of tumbler wheelshaving outwardly opening notches formed therein rotatably mounted on thespindle and interconnected in lost motion driving connection to eachother and to the cam means when the spindle is in its normal position oflongitudinal movement, said cam means driving connection beinginterrupted when the spindle is moved from its normal to a secondlongitudinal position, movable bolt means having a cam follower tongueand a fence operably connected thereto, the fence being received in thetumbler wheel notches when said notches are aligned at a predeterminedposition and permitting the cam follower tongue to engage the cam meansdrive notch when the spindle is moved from its normal to said secondlongitudinal positionand rotated thereby retracting the bolt means, thefence resting on the tumbler wheels maintaining the cam follower tonguedisengaged from the cam means when the tumbler wheel slots are notaligned at said predetermined position and when the spindle is thenmoved from its normal to said second longitudinal position, and the camfollower tongue resting on the cam means and maintaining the fencespaced from the tumbler wheels when the spindle is in its normalposition; the improvements including a tapered outer peripheral surfaceformed on the cam means, the cam follower tongue being engaged by saidtapered surface when the spindle and cam means are moved from saidsecond longitudinal position to normal position and when the tumblerwheel notches are not aligned at said predetermined position, the camfollower tongue initially engaging said tapered surface after partialmovement of the cam means from second to normal ,position, and remainingengaged with said surface after such initial engagement and during theremaining movement of. the cam means to normal position, falseengagementmeans independent of the cam follower tongue and independentof said engagement of the cam follower tonguewith the cam means, saidfalse engagement means including a circumferentially extending grooveformed-in the tapered cam surface of the camspaced axially from the endsof the cam means and opening radially outwardly of the tapered outerperipheral surface, and said false engagement means also including aseries of longitudinally spaced springpressed balls engageable with thecam groove and tapered cam surface at longitudinally spaced intervals asthe cam means is moved from its second longitudinal position to itsnormal position.

9. In a combination lock of the kind having a case, a longitudinallymovable spindle rotatably mounted extending partially into the case,dial means mounted on the spindle outside of the case, generallycylindrical cam means having a drive notch formed therein mounted on thespindle within the case, said dial and cam means being rotatable andlongitudinally movable with the spindle, a series of tumbler wheelshaving outwardly opening notches formed therein rotatably mounted on thespindle and interconnected in lost motion driving connection to eachother and to the cam means when the spindle is in its normal position oflongitudinal movement, said cam means driving connection beinginterrupted when the spindle is moved from its normal to a secondlongitudinal position, movable bolt means having a cam follower tongueand a fence operably connected thereto, the fence being received in thetumbler wheel notches when said notches are aligned at a predeterminedposition and permitting the cam follower tongue to engage the cam me'ansdrive notch when the spindle is moved from its normal to said secondlongitudinal position and rotated thereby retracting the bolt means, thefence resting on the tumbler wheels maintaining the cam follower tonguedisengaged from the cam means when the tumbler 'wheel slots are notaligned at said predetermined position and whenthe spindle is then movedfrom its normal to said second longitudinal position, and the camfollower tongue resting on the cam means and maintaining the fencespaced from the tumbler wheels when the spindle is in its normalposition; the

improvements including a tapered outer peripheral surface formed on thecam means, the cam follower tongue being engaged by said tapered surfacewhen the spindle and cam means are moved from said second longitudinalposition to normal position and when the tumbler wheel notches are notaligned at said predetermined position, the cam follower tongueinitially engaging said tapered surface after partial movement of thecam means from second to normal position and remaining engaged with saidsurface after such initial engagement and during the remaining movementof the cam means to normal position, false engagement means independentof the cam follower tongue including a series of longitudinally spacedspring-pressed balls mounted on the case and engageable with the cammeans at longitudinally spaced intervals as the cam means is moved fromits second longitudinal position to its normal position for masking saidinitial engagement of the cam follower tongue with :18 the cam means,and guide means mounted on theme and engageable with the cam followertongue for requiring movement of the tongue in a predetermined planeperpendicular to the axis of the spindle.

10. In a combination lock of the kind having a case, a longitudinallymovable spindle rotatably mounted extending partially into the case,dial means mounted on the spindle outside of the case, generallycylindrical cam means having a drive notch formed therein mounted on thespindle within the case, said dial and cam means being rotatable andlongitudinally movable with the spindle, a series of tumbler wheelshaving outwardly opening notches formed therein rotatably mounted on thespindle and interconnected in lost motion driving con-' nection to eachother and to the cam means when the spindle is in its normal position oflongitudinal movement, said cam means driving connection beinginterrupted when the spindle is moved from its normal to a secondlongitudinal position, movable bolt means having a cam follower tongueand a fence operably connected thereto, the fence being received in thetumbler wheel notches when said notches are aligned at a predeter-'mined position and permitting the cam follower tongue to engage the cammeans drive notch when the spindle is moved from its normal to saidsecond longitudinal position and rotated thereby retracting the boltmeans, the fence resting on the tumbler wheels maintaining the camfollower tongue disengaged from the cam means when the tumbler wheelslots are not aligned at said predetermined position and when thespindle is then moved from its normal to said second longitudinalposition, and the cam follower tongue resting on the cam means andmaintaining the fence spaced from the tumbler wheels when the spindle isin its normal position; the improvements including a tapered outerperipheral surface formed on the cam means, the cam follower tonguebeing engaged by said tapered surface when the spindle and cam means aremoved from said second longitudinal position to normal position and whenthe tumbler wheel notches are not aligned at said predeterminedposition, the cam follower tongue initially engaging said taperedsurface after partial movement of the cam means from second to normalposition and remaining engaged with said surface after such initialengagement and during the remaining movement of the cam means to normalposition, the cam means tapered surface being uniformly tapered andbeing formed of nylon, false engagement means independent of the camfollower tongue including a circumferentially extending groove formed inthe cam means tapered surface spaced axially from the ends of the cammeans and opening radially outwardly of the tapered outer peripheralsurface, the cam follower tongue being formed of metal, a guide yokeengageable with the cam follower tongue and having a guide slot formedtherein requiring movement of the tongue in a predetermined planeperpendicular to the axis of the spindle, at

least one of the surfaces of said guide slot being formed" of nylon, andsaid false engagement means also including a series of longitudinallyspaced spring-pressed balls engageable with the cam groove and taperedcamsurface at longitudinally spaced intervals as the cam means is movedfrom its second longitudinal position to its normal position to mask theinitial engagement of the cam follower tongue with the cam means.

11. In a combination lock of the kind having a case, a longitudinallymovable spindle rotatably mounted extending partially into the case,dial means mounted on the spindle outside of the case, generallycylindrical cam means having a drive notch formed therein mounted on thespindle within the case, said dial and cam means being rotatable andlongitudinally movable with the spindle, a series of tumbler wheelshaving outwardly opening notches formed therein rotatably mounted on thespindle and interconnected in lost motion driving con- 19 motion to eachother and to the cam means when the spindle is in its normal position oflongitudinal movement, said cam means driving connection beinginterrupted when the spindle is moved from its normal to a secondlongitudinal position, movable bolt means having acam follower tongueand a fence operably connected thereto, the fence being received in thetumbler wheel notches when said notches are aligned at a predeterminedposition and permitting the cam follower tongue to engage the cam meansdrive notch when the spindle is moved from its normal to said secondlongitudinal position and rotated thereby retracting the bolt means, thefence resting on the tumbler wheels maintaining the cam follower tonguedisengaged from the cam means when the tumbler wheel slots are notaligned at said predetermined position and when the spindle is thenmoved from its normal to said second longitudinal position, and the camfollower tongue resting on the cam means and maintaining the fencespaced from the tumbler wheels when the spindle is in its normalposition; i

the improvements including a tapered outer peripheral surface formed onthe cam means, the cam follower tongue being engaged by said taperedsurface when the spindle and cam means are moved from said secondlongitudinal position to normal position and when the tumbler. wheelnotches are not aligned at said predetermined position, the cam followertongue initially engaging said tapered surface after partial movement ofthe cam means from second to normal position and remaining engaged withsaid surface after such initial engagement and during the remainingmovement of the cam means to normal position, false engagement meansincluding engageable elements mounted on the lock independent of the camfollower tongue and independent of said engagement of the cam followertongue with the cam means, certain of said false engagement elementsbeing operably connected to and movable with the movable spindle, and atleast certain of said engageable elements moving to positions ofengagement with each other normally at a different time than saidengagement of the cam follower tongue with the cam means uponlongitudinal movement of the spindle, whereby separate false engagementindications are given establishing confusion with the indication ofsaidengagement of the cam follower tongue with the cam means, and spacedguide means mounted on the case and engageable with the cam followertongue for requireing movement of the tongue in a predetermined planeperpendicular to the axis of the spindle.

12. The combination lock construction defined in claim 11 in which thespaced guide means includes a guide yoke mounted on the case and havinga guide slot formed therein engageable with the cam follower tongue.

13. In a combination lock of the kind having a case, a longitudinallymovable spindle rotatably mounted extending partially into the case,dial means mounted on the spindle outside of the case, generallycylindrical cam means having a drive notch formed therein mounted on thespindle within the case, said dial and cam means being rotatable andlongitudinally movable with the spindle, a series of tumbler wheelshaving outwardly opening notches formed therein rotatably mounted on thespindle and interconnected in lost motion driving connection to eachother and to the cam means when the spindle is in its normal position oflongitudinal movement, said cam means driving connection beinginterrupted when the spindle is moved from its normal to a; secondlongitudinal position, movable bolt means having a cam follower tongueand a fence operably connected thereto, the fence being re ceived in thetumbler wheel notches when said notches are aligned at a predeterminedposition and permitting the cam follower tongue to engage the cam meansdrive notch When the spindle is moved from its normal to said secondlongitudinal position and rotated thereby retracting the bolt means, thefence resting on the tumbler wheels maintaining the cam follower tonguedisengaged from the cam means when the tumbler wheel slots are notaligned at said predetermined position and when the spindle is thenmoved from its normal to said second longitudinal position, and the camfollower tongue resting on the cam means and maintaining the fencespaced from the tumbler wheels when the spindle is in its normalposition; the improvements including a tapered outer peripheral surfaceformed on the cam means, the cam follower tongue being engaged by saidtapered surface when the spindle and cam means are moved from saidsecond longitudinal position to normal position and when the tumblerWheel notches are not aligned at said predetermined position, the camfollower tongue initially engaging said tapered surface after partialmovement of the cam means from second to normal position and remainingengaged with said surface after such initial engagement and during theremaining movement of the cam means to normal position, the cam meansbeing formed of nylon, false engagement means independent of the camfollower tongue and independent of said engagement of the cam followertongue with the cam means, said false engagement means including acircumferentially extending groove formed in the cam means taperedsurface spaced axially from the ends of the cam and opening radiallyoutwardly of the tapered outer peripheral surface, the cam followertongue being formed of metal, said false engagement means also includingresilient means mounted for engagement with the cam groove and surfacenormally at a different time than said engagement of the cam followertongue with the cam means upon longitudinal movement of the spindle,whereby separate false engagement indications are given cstablishingconfusion with the indication of said engagement of the cam followertongue with the cam means, and guide means engagea'ble with the camfollower tongue for requiring movement of the tongue in a predeterminedplane perpendicular to the axis of the spindle.

References Cited in the file of this patent UNITED STATES PATENTS 79,388Pillard June 30, 1868 237,950 Bernhardt Feb. 22, 1881 304,203 JoerdenAug. 26, 1884 550,655 Stone Dec. 3, 1895 1,956,304 Abbott et al Apr. 24,1934 2,775,113 Behrens Dec. 25, 1956 2,775,115 Bremer Dec. 25, 1956

